﻿//
// (C) Copyright 2009 Irantha Suwandarathna (iranthas@hotmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace EffiProz.Core.Lib
{
    public class WrapperIterator : Iterator
    {
        private static Object[] emptyelements = new Object[0];
        private Object[] elements;
        private int i;

        // chained iterators
        private bool chained;
        private Iterator it1;
        private Iterator it2;

        /** return only not null elements */
        private bool notNull;

        /**
         * Constructor for an empty iterator. <p>
         */
        public WrapperIterator()
        {
            this.elements = emptyelements;
        }

        /**
         * Constructor for all elements of the specified array. <p>
         *
         * @param elements the array of objects to enumerate
         */
        public WrapperIterator(Object[] elements)
        {
            this.elements = elements;
        }

        /**
         * Constructor for not-null elements of specified array. <p>
         *
         * @param elements the array of objects to iterate
         */
        public WrapperIterator(Object[] elements, bool notNull)
        {
            this.elements = elements;
            this.notNull = notNull;
        }

        /**
         * Constructor for a singleton object iterator
         *
         * @param element the single object to iterate
         */
        public WrapperIterator(Object element)
        {
            this.elements = new Object[] { element };
        }

        /**
         * Constructor for a chained iterator that returns the elements of the two
         * specified iterators.
         */
        public WrapperIterator(Iterator it1, Iterator it2)
        {

            this.it1 = it1;
            this.it2 = it2;
            chained = true;
        }

        /**
         * Tests if this iterator contains more elements. <p>
         *
         * @return  <code>true</code> if this iterator contains more elements;
         *          <code>false</code> otherwise.
         */
        public bool hasNext()
        {

            // for chained iterators
            if (chained)
            {
                if (it1 == null)
                {
                    if (it2 == null)
                    {
                        return false;
                    }

                    if (it2.hasNext())
                    {
                        return true;
                    }

                    it2 = null;

                    return false;
                }
                else
                {
                    if (it1.hasNext())
                    {
                        return true;
                    }

                    it1 = null;

                    return hasNext();
                }
            }

            // for other interators
            if (elements == null)
            {
                return false;
            }

            for (; notNull && i < elements.Length && elements[i] == null; i++) { }

            if (i < elements.Length)
            {
                return true;
            }
            else
            {

                // release elements for garbage collection
                elements = null;

                return false;
            }
        }

        /**
         * Returns the next element.
         *
         * @return the next element
         * @throws NoSuchElementException if there is no next element
         */
        public Object next()
        {

            // for chained iterators
            if (chained)
            {
                if (it1 == null)
                {
                    if (it2 == null)
                    {
                        throw new KeyNotFoundException();
                    }

                    if (it2.hasNext())
                    {
                        return it2.next();
                    }

                    it2 = null;

                    next();
                }
                else
                {
                    if (it1.hasNext())
                    {
                        return it1.next();
                    }

                    it1 = null;

                    next();
                }
            }

            // for other itertors
            if (hasNext())
            {
                return elements[i++];
            }

            throw new KeyNotFoundException();
        }

        public int nextInt()
        {
            throw new KeyNotFoundException();
        }

        public long nextLong()
        {
            throw new KeyNotFoundException();
        }

        public void remove()
        {
            throw new KeyNotFoundException();
        }

        public void setValue(Object value)
        {
            throw new KeyNotFoundException();
        }
    }
}
